JP2007242848A - Manufacturing method and treating apparatus for substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a substrate capable of removing an Mo oxide, and suppressing the adhesion of the Mo oxide to the substrate without increasing the number of processes. <P>SOLUTION: In the manufacturing method for the substrate, a layer containing molybdenum is formed on a substrate, and atmospheric pressure plasma treatment using at least nitrogen gas is carried out for the substrate in a state wherein the layer containing molybdenum is exposed. Thus, the manufacturing method for the substrate capable of removing the Mo oxide and suppressing the adhesion of the Mo oxide to the substrate without increasing the number of processes is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a substrate on which a layer containing molybdenum is formed and a substrate processing apparatus.

In recent years, electrodes and wiring materials of thin film transistors for liquid crystal display devices (hereinafter referred to as TFTs) have been changed from conventional chromium (hereinafter referred to as Cr) materials to aluminum (hereinafter referred to as Al) or molybdenum (hereinafter referred to as Al) materials having low wiring resistance. Hereinafter, a material of Mo) is used. However, Mo is easily oxidized, and Mo oxide has a property of being easily dissolved in water or the like. Therefore, when Mo is used for an electrode of a TFT or the like, there arises a problem that Mo oxide (MoO _x ) generated on the Mo surface is dissolved in the cleaning liquid in the cleaning process. The secondary contamination that Mo oxide dissolved in the cleaning liquid re-adheres to the TFT after drying the substrate occurs, which causes malfunction of the TFT such as display unevenness.

  The above problem will be described with reference to FIG. 5, taking the cross-sectional structure of an inverted staggered a-Si (amorphous silicon) TFT as an example. The inverted staggered a-Si TFT has the most manufactured structure as a TFT for a liquid crystal display device.

As shown in FIG. 5, the inverted staggered a-Si TFT 121 includes a gate electrode layer 123 formed on a substrate 122 made of glass or the like, and then a gate insulating layer 124, a semiconductor layer 125, and an ohmic contact layer 126. Continuous film formation and patterning. The semiconductor layer 125 is formed as a channel layer and is made of amorphous silicon (a-Si). The ohmic contact layer 126 is formed as an ohmic contact between the semiconductor layer 125 and the electrode, and is made of low-resistance amorphous silicon (n ⁺ a-Si). After that, a material containing Mo is formed as the source electrode layer 127 and the drain electrode layer 128 and patterned. After the patterning, the resist used for forming the source electrode layer 127 and the drain electrode layer 128 is removed.

  When Mo is contained in the surfaces of the source electrode layer 127 and the drain electrode layer 128, Mo oxide is generated on the surface of the electrode layer by oxidation. This Mo oxide has the property of being easily dissolved in water or an alkaline liquid. Therefore, when pure water cleaning is performed to remove the resistor after the source electrode layer 127 and the drain electrode layer 128 are formed, Mo oxide may be dissolved in the cleaning liquid. Thereafter, when the TFT 121 immersed in the cleaning liquid is dried, the Mo oxide 130 is deposited on the TFT 121.

  When the deposited Mo oxide 130 adheres to the channel surface of the TFT 121 as shown in FIG. 5, surface leakage current easily flows through the Mo oxide 130. Therefore, the on / off control of the TFT 121 cannot be performed, and the current-voltage characteristics are deteriorated. As a result, there arises a problem that image defects such as image unevenness of the liquid crystal display device using the TFT 121 occur.

A technique for solving the adhesion of the Mo oxide film is disclosed in Patent Document 1. FIG. 6 shows a schematic diagram of the embodiment. As shown in FIG. 6, by applying hexamethyldisilazane ((CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ ) on a substrate having a Mo oxide 130 formed on the surface and heating, Reacts with a hydroxyl group (OH) to generate ammonia (NH ₄ ). This ammonia and the Mo oxide 130 are combined to form (NH ₄ ) ₂ Mo ₃ O ₁₀ , and the Mo oxide 130 can be removed. After the Mo-containing wiring 131 is formed, the display defect due to the Mo oxide 130 is prevented by removing the Mo oxide 130 before performing the cleaning process.

  Patent Document 2 discloses a technique for removing organic substances remaining on the source and drain electrode layers formed of Mo. This organic substance is a residue of the organic insulating film formed on the source electrode layer and the drain electrode layer, and a technique is disclosed in which the organic substance remaining in the opening of the organic insulating film is removed by oxygen plasma. As described above, this is different from the technique for removing the Mo oxide dissolved from the Mo wiring.

Patent Document 3 discloses a technique of adding nitrogen to a Mo and Al-based source electrode layer and drain electrode layer having a two-layer structure when forming Mo. By adding nitrogen to Mo, the etching rate of Mo and Al-based metal is made close so that two layers can be etched simultaneously. Therefore, it is different from the technique for removing Mo oxide dissolved from the Mo wiring as described above.
Japanese Patent Application Laid-Open No. 7-30119 Japanese Patent Laid-Open No. 10-135465 JP 09-148586 A

  With the configuration of Patent Document 1, it is possible to prevent the display quality from being deteriorated by removing the precipitated Mo oxide. However, this method adds a processing step for removing the Mo oxide film to a step for forming a normal thin film pattern. Therefore, this results in an increase in the number of manufacturing process steps, resulting in a problem that manufacturing productivity is reduced.

  In addition, even after removing the Mo oxide, if the Mo-containing layer is left in the atmosphere even for a short time, Mo oxide may be generated again on the surface, and the Mo oxide must be completely removed. I can't.

  An object of this invention is to provide the manufacturing method and substrate processing apparatus of a board | substrate which suppress the adhesion to the board | substrate of Mo oxide while removing Mo oxide, without increasing the number of processes.

  According to the substrate manufacturing method of the present invention, a layer containing molybdenum is formed on a substrate, and the substrate is subjected to atmospheric pressure plasma treatment using at least nitrogen gas in a state where the layer containing molybdenum is exposed. It is.

  Further, the substrate processing apparatus according to the present invention removes molybdenum oxide formed on the molybdenum-containing layer from the substrate formed by exposing the molybdenum-containing layer to form molybdenum nitride. An atmospheric pressure plasma processing unit is provided.

  The wiring board according to the present invention includes molybdenum nitride formed on the surface of the layer containing molybdenum in the layer containing molybdenum formed on the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and substrate processing apparatus of a board | substrate which suppress the adhesion to the board | substrate of Mo oxide while removing Mo oxide can be provided, without increasing the number of processes.

  The preferred embodiments of the present invention will be described below. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. For the sake of clarification, duplicate explanation is omitted as necessary.

Embodiment 1
First, a liquid crystal display device (not shown) according to the present embodiment will be described. First, a TFT array substrate in which TFTs and electrode lines and storage capacitors are formed on a glass substrate, and a counter substrate in which common electrodes and R (red), G (green), and B (blue) color filters are formed on the glass substrate Are bonded together using a sealant. Thereafter, liquid crystal is injected into the gap between the substrates, and the injection port is sealed with a sealant to form a liquid crystal panel. Next, the driving circuit board on which the driving LSI and the panel control IC are mounted is connected to the liquid crystal panel. Further, the backlight unit is disposed on the back of the TFT array substrate, and the liquid crystal display device is completed. In this liquid crystal display device, an image can be displayed by a liquid crystal panel driven by a drive circuit controlling transmission of light from the backlight unit.

  Next, a manufacturing method of the TFT array substrate will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the configuration of the TFT 21 including the pixel electrode portion, but the other portions are omitted. First, the substrate 22 formed of, for example, light transmissive glass, polycarbonate, acrylic resin, or the like is cleaned using pure water, acid, or the like. Next, the gate electrode layer 23 is formed. Specifically, for example, a molybdenum tantalum (MoTa) film is formed on the substrate 22 by a sputtering method. Next, a photoresist is applied on the MoTa film, and after baking, a predetermined pattern shape is masked to perform exposure processing. Thereafter, the photoresist is patterned by developing with, for example, an organic alkaline developer. Next, wet etching is performed using, for example, a mixed solution of phosphoric acid and nitric acid. Thereby, the MoTa film is formed in a desired pattern shape. Then, the photoresist is removed from the substrate 22, and the substrate 22 from which the photoresist has been removed is washed. Through the above steps, a gate electrode layer 23 is formed on the substrate 22, and this gate electrode layer 23 is used as a gate wiring.

  Next, the gate insulating layer 24 is formed so as to cover the gate electrode layer 23 on the substrate 22 by using a chemical vapor deposition (CVD) method. Similarly, an amorphous silicon film that is a material of the semiconductor layer 25 is deposited on the gate insulating layer 24. Further, the amorphous silicon layer is ion-doped to form an n + amorphous silicon film, and the ohmic contact layer 26 is formed. A resist pattern is formed on this laminate and dry etching is performed. The n + amorphous silicon film, the amorphous silicon film, and the silicon nitride (SiN) film are etched to form a desired pattern shape. Then, the photoresist is removed from the substrate 22, and the substrate 22 from which the photoresist has been removed is washed. Through the above steps, the semiconductor layer 25, the gate insulating layer 24, and the ohmic contact layer 26 are formed on the substrate 22.

  Next, the source electrode layer 27 and the drain electrode layer 28 are formed. First, a metal film for forming the source electrode layer 27 and the drain electrode layer 28 is formed by a sputtering method. For example, a Mo—Al—Mo laminated film is formed on the substrate. After forming a resist pattern on the laminated film, channel etching is performed by dry etching. As a result, the Mo—Al—Mo laminated film is formed in a desired pattern shape, and a wiring in which the source electrode layer 27 and the drain electrode layer 28 are used as a source wiring is formed. Then, the photoresist is removed from the substrate 22, and the substrate 22 from which the photoresist has been removed is washed. A specific cleaning method will be described in detail later. At this stage, a process for forming a nitride on the surface of the wiring containing Mo is performed.

  Subsequently, a passivation film 29 is formed on the source electrode layer 27 and the drain electrode layer 28. The passivation film 29 is formed so as to cover the source electrode layer 27 and the drain electrode layer 28. First, a silicon nitride (SiN) film that is a material of the passivation film 29 is formed on the substrate 22 by, for example, a CVD method. A resist pattern is formed thereon, and dry etching is performed using fluorine (F) gas or the like. Thereby, a contact hole 31 is formed in the passivation film 29. Then, the photoresist is removed from the substrate 22, and the substrate 22 from which the photoresist has been removed is washed.

  Next, a pixel electrode is formed. First, a transparent conductive film (for example, an ITO film) serving as a material for the pixel electrode is formed on the substrate 22 by sputtering. At this time, an ITO film is also formed inside the contact hole 31, and the drain electrode layer 28 and the ITO film are connected. Next, a resist pattern is formed and wet etching is performed. Thereby, the ITO film is formed in a desired pattern shape. The photoresist is removed from the substrate 22, and the substrate 22 from which the photoresist has been removed is washed. Through the above steps, a TFT array substrate for a liquid crystal display device is completed.

  With reference to FIG. 2, the resist removal and cleaning method for manufacturing the TFT 21 will be described in detail. FIG. 2 is a configuration diagram of the substrate processing apparatus according to the present embodiment. FIG. 2 shows a substrate processing apparatus 1 having a loader 11, an inlet conveyor 12, a peeling processing unit A13, a peeling processing unit B14, a cleaning unit 15, a drying unit 16, an outlet conveyor 17, an unloader 18, and an atmospheric pressure plasma processing unit 19. is there. In the present embodiment, among TFT manufacturing processes, a resist removal and cleaning process is performed in a state where a Mo-containing layer is exposed after a Mo-containing wiring layer is formed.

  First, a cassette containing a substrate on which the TFT 21 is formed (hereinafter referred to as a TFT substrate) is installed in the loader 11. The TFT substrate is extracted by moving means such as a robot and transferred to the entrance conveyor 12. Thereafter, the TFT substrate is immersed in a stripping solution in the stripping unit A13 and stripping unit B14. Thereby, the resist residue remaining on the TFT substrate is removed. The cleaning unit 15 then rinses the TFT substrate with pure water to wash away the stripping solution. Next, after the TFT substrate is dried by the drying unit 16, the TFT substrate is conveyed to the outlet conveyor 17. At that time, the atmospheric pressure plasma processing is performed by the atmospheric pressure plasma processing unit 19 on the TFT substrate passing through the outlet conveyor 17. The TFT substrate subjected to the atmospheric pressure plasma treatment is accommodated in a cassette of the unloader 18 by a moving means such as a robot. These series of cleaning operations can be performed automatically and are controlled by a controller (not shown). Of course, it is also possible to perform a series of operations manually.

  In the peeling processing unit A13 and the peeling processing unit B14, the resist residue remaining on the TFT substrate is removed by dipping in a resist stripping solution. The resist stripping solution removes resist residues remaining in fine locations in a short time without degrading the wiring material or the material having low chemical resistance. There are many types of resist stripping solutions such as an organic cleaning solution using acetone and alcohol, and an acid-alkali cleaning solution using hydrogen peroxide solution or ammonia solvent. Since each resist has a designated stripping solution depending on the type, a plurality of stripping processing units can be provided and used separately for each resist. It is also possible to inject the same stripping solution into a plurality of stripping processing units and divide into rough cleaning and finish cleaning.

In the cleaning unit 15, the resist stripping solution adhering to the TFT substrate surface and foreign matters such as particles are removed by the cleaning solution. In this embodiment, pure water is used as the cleaning liquid. Pure water has impurities removed as much as possible and is also called ion-exchanged water or deionized water. In a general semiconductor manufacturing process, water whose electrical conductivity is lowered to about 1 × 10 ⁻⁶ S / cm or less is used. Depending on the degree of integration of the circuit, pure water with higher purity, whose electrical conductivity is lowered to 6 × 10 ⁻⁸ S / cm or less, may be used.

  In the atmospheric pressure plasma processing unit 19, a glow discharge state that can only be generated under normal vacuum is generated under atmospheric pressure by a special method. In the atmospheric pressure plasma processing unit 19, cleaning such as organic substance removal is performed using the plasma active species generated thereby. Atmospheric pressure plasma treatment removes the surface layer and forms a new surface layer with altered chemical composition and structure. Atmospheric pressure plasma treatment can improve the adhesiveness by utilizing an active effect such as a rough surface effect or surface treatment for forming an uneven shape on the surface. In addition, application to film formation is possible as represented by application to CVD method and the like.

  FIG. 3 shows a configuration example of the atmospheric pressure plasma processing unit 19. The atmospheric pressure plasma processing unit 19 includes, for example, a power application electrode 33 and a ground electrode 35 in a chamber 34 into which gas is introduced. As for the configuration of the atmospheric pressure plasma processing unit 19, other structures that can be considered by those skilled in the art can be used. A mixed gas for plasma generation such as oxygen or nitrogen is introduced into the chamber 34, and a voltage is applied to the gas to generate a plasma 37. The generated plasma 37 collides with the TFT substrate 36 transported directly under the atmospheric pressure plasma processing unit 19 to remove organic substances on the TFT substrate 36. In addition to oxygen and nitrogen, argon, helium, air, or the like can be used as the plasma generating gas. In this embodiment, nitrogen and oxygen are used. Although the atmospheric pressure plasma processing unit 19 is disposed on the exit conveyor 17, it can be disposed at any position on the substrate transport path after resist removal.

In the present embodiment, an example of conditions of atmospheric pressure plasma processing by the atmospheric pressure plasma processing unit 19 is a mixed gas having a nitrogen flow rate of 400 L / min and an oxygen flow rate of 1.69 × 10 ⁻¹ Pa · m ³ / sec (100 SCCM). The distance between the substrate and the electrode is 3 mm, and the substrate transport speed is 1 m / min. By performing atmospheric pressure plasma treatment under the above processing conditions, Mo oxide formed on the surfaces of the source electrode layer 27 and the drain electrode layer 28 is removed, and Mo nitridation is performed on the surfaces of the source electrode layer 27 and the drain electrode layer 28. A product (hereinafter referred to as a MoNx layer). The values of the above processing conditions are values when the substrate dimension in the direction perpendicular to the substrate transport direction is 400 mm, and it is necessary to increase the length of the electrode in order to increase the substrate dimension. In addition, the nitrogen flow rate and the oxygen flow rate must be increased accordingly.

  In the source electrode layer 27 and the drain electrode layer 28 containing Mo, Mo oxide is formed on the surface by oxygen in the atmosphere immediately after the resist is removed from the pattern. Here, by performing the atmospheric pressure plasma treatment by the atmospheric pressure plasma treatment unit 19, the Mo oxide formed on the surface layer is removed, and a new MoNx layer is formed. FIG. 4 is an enlarged cross-sectional view of a part of FIG. As shown in FIG. 4, MoNx layer 32 is generated on the surface layer of Mo-containing source electrode layer 27 and drain electrode layer 28 by performing atmospheric pressure plasma treatment. Therefore, even if the TFT substrate is left in the atmosphere after the atmospheric pressure plasma treatment, the MoNx layer is formed on the Mo surface, so that the formation of Mo oxide is suppressed. What is important here is that at least nitrogen must be used in the atmospheric pressure plasma treatment in order to form the NoNx layer.

  For example, when the atmospheric pressure plasma treatment is performed after the source electrode layer 27 and the drain electrode layer 28 are formed and the resist is peeled off, the pure water cleaning may be performed in the next cleaning before forming the passivation film. The Mo oxide does not dissolve in the cleaning liquid. That is, MoNx layers are formed on the surfaces of the source electrode layer 27 and the drain electrode layer 28 by atmospheric pressure plasma treatment.

  The cleaning process is also performed after patterning the contact hole 31 for connecting the drain electrode layer 28 and the ITO film on the passivation film 29 and stripping the resist. However, since the MoNx layer by the atmospheric pressure plasma treatment has already been formed on the surface of the drain electrode layer 28, the Mo oxide does not dissolve in the cleaning liquid. The MoNx layer needs to be a conductive layer.

  Further, in the subsequent cleaning before forming the ITO film, the cleaning process is performed, but similarly, Mo oxide does not dissolve in the cleaning liquid. As described above, after the atmospheric pressure plasma treatment is performed, the MoNx layer is formed on the Mo-containing layer and the generation of Mo oxide is suppressed, so that the Mo oxide is dissolved in the cleaning liquid during the pure water cleaning of the substrate. Can be prevented. Therefore, no Mo oxide precipitates on the TFT 21 during the drying process after cleaning. As a result, display defects such as image unevenness of the liquid crystal display device can be prevented without causing surface leakage current of the TFT 21 due to the deposited Mo oxide.

  In this embodiment, the atmospheric pressure plasma treatment is performed after the resist stripping process of the source electrode layer 27 and the drain electrode layer 28. However, it may be performed at the end of the cleaning process before the passivation film 29 is formed. Similarly, it can be performed after the resist stripping process of the passivation film 29. Furthermore, it is also possible to carry out atmospheric pressure plasma treatment at the end of the pre-deposition cleaning step for the ITO film or the like thereafter.

  With the configuration as described above, even when a metal containing Mo is used as the wiring material, Mo oxide deposited on the TFT 21 can be removed, and at the same time, a MoNx layer is formed on the Mo surface. Oxide formation can be suppressed. As a result, the Mo oxide dissolved in the cleaning process does not adhere to the TFT 21 again, and the TFT 21 with good electrical characteristics can be obtained.

  In addition, with the above configuration, atmospheric pressure plasma treatment can be performed in a series of operations in the resist stripping and cleaning steps. Therefore, removal of Mo oxide and dissolution of Mo oxide into the cleaning liquid can be eliminated without increasing the number of manufacturing steps.

  Moreover, by suppressing the dissolution of Mo oxide into the cleaning liquid, the replacement frequency of the cleaning liquid is reduced, and the material cost of the cleaning liquid and the labor cost due to the replacement can be reduced.

  In addition, this invention is not limited to said embodiment. Within the scope of the present invention, each element of the above-described embodiment can be changed, added, or converted into contents that can be easily considered by those skilled in the art. For example, although the above embodiment has been described in the case where Mo material is used for the source electrode layer and the drain electrode layer electrode layer, the same is possible even when Mo material is used for other wiring. Furthermore, although the case where the source electrode layer and the drain electrode layer are Mo—Al—Mo laminated films has been described, the same effect can be obtained with a Mo single layer film or other film configurations including Mo.

  In addition, not only the TFT array substrate in the liquid crystal display device, but the same can be applied to the substrate manufacturing using Mo oxide. Furthermore, the preferred embodiment of the present invention has been described by taking the manufacturing process of the TFT array substrate in the liquid crystal display device as an example. Is possible. That is, the present invention is not limited to a liquid crystal display device and can be generally applied to manufacture of a substrate having a layer containing Mo.

It is sectional drawing of the thin-film transistor for liquid crystal displays which concerns on this invention. The block diagram of the substrate processing apparatus which concerns on this invention is shown. It is a block diagram of the atmospheric pressure plasma processing part which concerns on this invention. It is sectional drawing which shows the state of Mo layer concerning this invention. It is sectional drawing which shows the state of the thin-film transistor for liquid crystal display devices in which Mo oxide precipitated. It is a schematic diagram of the method of removing Mo oxide by patent document 1. FIG.

Explanation of symbols

1 substrate processing equipment,
11 loader, 12 inlet conveyor,
13 Peeling treatment unit A, 14 Peeling treatment unit B,
15 washing unit, 16 drying unit,
17 outlet conveyor, 18 unloader,
19 Atmospheric pressure plasma treatment section,
21 TFT,
22 substrate, 23 gate electrode layer,
24 gate insulating layer, 25 semiconductor layer,
26 ohmic contact layer,
27 source electrode layer, 28 drain electrode layer,
29 passivation film, 31 contact hole,
32 MoNx layer,
33 electrode for power supply, 34 chamber,
35 Ground electrode, 36 TFT substrate, 37 Plasma 121 TFT,
122 substrate, 123 gate electrode layer,
124 gate insulating layer, 125 semiconductor layer,
126 ohmic contact layer,
127 source electrode layer, 128 drain electrode layer,
129 passivation film, 130 Mo oxide,
131 Mo wiring

Claims (8)

Forming a layer containing molybdenum on the substrate;
A method for manufacturing a substrate, wherein the substrate is subjected to an atmospheric pressure plasma treatment using at least nitrogen gas in a state where the layer containing molybdenum is exposed.   The method for manufacturing a substrate according to claim 1, wherein molybdenum nitride is formed on the surface of the layer containing molybdenum by the atmospheric pressure plasma treatment. The atmospheric pressure plasma treatment is performed using a mixed gas having a nitrogen flow rate of 400 L / min and an oxygen flow rate of 1.69 × 10 ⁻¹ Pa · m ³ / sec (100 SCCM), a distance between the substrate and the electrode of 3 mm, The method for manufacturing a substrate according to claim 1, wherein the conveyance speed is 1 m / min. For a substrate formed by exposing a layer containing molybdenum,
A substrate processing apparatus comprising an atmospheric pressure plasma processing unit for removing molybdenum oxide formed in the molybdenum-containing layer to form molybdenum nitride.   The substrate processing apparatus according to claim 4, wherein the atmospheric pressure plasma processing unit uses at least nitrogen gas. The processing conditions in the atmospheric pressure plasma processing section are a mixed gas having a nitrogen flow rate of 400 L / min and an oxygen flow rate of 1.69 × 10 ⁻¹ Pa · m ³ / sec (100 SCCM), and the distance between the substrate and the electrode is 3 mm, The substrate processing apparatus according to claim 4, wherein the substrate transfer speed is 1 m / min. In the layer containing molybdenum formed on the substrate,
A wiring board having molybdenum nitride formed on a surface of the layer containing molybdenum.   The wiring board according to claim 7, wherein the molybdenum nitride is formed by atmospheric pressure plasma treatment.

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